1. Field of the Invention
This invention relates generally to metal alloys, and more particularly, relates to compositions of certain silver alloy for use in jewelry, flatware, and the like.
2. Description of the Related Art
Sterling silver is commonly used for jewelry and flatware manufacturing. Classic or regular sterling typically contains about 92.5% by weight silver and 7.5% by weight copper. Its use dates back to at least as early as the 14th Century. In modern times, sterling silver alloys may include elements other than silver and copper. However, the silver content of conventional sterling silver compositions has generally remained at 92.5% or higher.
Unlike karat gold alloys, regular sterling silver is expected to tarnish readily due to formation of copper oxides, and silver and copper sulfides. As a result, a number of different sterling silver alloys have been developed to improve the alloy's resistance to tarnishing. This is typically achieved by reducing the copper content to minimize the oxidation, and by adding some elements of oxides which serve as a protection against tarnish. While some of these silver alloys are formulated to have higher tarnish resistance than that of regular sterling silver, there is still a need for silver alloys with more improved tarnish resistance.